Integrated optical temperature measurement sensing chip, optical temperature measurement sensing device and temperature measurement method

Abstract

The present invention discloses an integrated optical temperature sensing chip, an optical temperature sensing device and a temperature measurement method. Among them, the integrated optical temperature sensing chip includes a wafer substrate and an integrated optical path disposed on the wafer substrate. The integrated optical path includes a closed-loop integrated optical resonator and an open-loop bus optical waveguide, and a coupling region is formed between the bus optical waveguide and the integrated optical resonator. Based on the principle that the difference between the resonance frequencies of two orthogonal polarization modes changes with the change of the cavity temperature, through the PDH (Pound-Drever-Hall) frequency locking technology, the frequency of the tunable laser is locked on one polarization resonance frequency of the integrated optical resonator, and the sideband modulation frequency is locked on the difference between the resonance frequencies of two orthogonal polarization modes, realizing the real-time tracking of the sideband modulation frequency to the difference between the resonance frequencies of two orthogonal polarization modes; by monitoring the change of the sideband modulation frequency, the accurate measurement of the temperature change of the integrated optical resonator is realized.

Description

Technical Field

[0001] The present invention relates to the field of precision sensing technology, and particularly to an integrated optical temperature sensing chip, an optical temperature sensing device, and a temperature measurement method. Background Art

[0002] Planar integrated optical circuits are widely used in fields such as optical communication, quantum optics, nonlinear optics, and spatio-temporal measurement. Many precision optoelectronic devices and systems are miniaturized and integrated in the form of integrated optical circuits. Therefore, the optical properties of integrated optical devices directly determine the performance of these miniaturized optoelectronic devices and systems. The thermal stability of integrated optical devices is one of the important factors affecting their optical properties. For example, changes in the device temperature will change the refractive index of the material, thereby affecting the propagation optical path and phase difference, and ultimately leading to changes in the functions and performance of optical devices. Accurately measuring the temperature change of optical devices and suppressing and compensating for temperature noise are effective methods to improve the thermal stability of integrated optical devices.

[0003] However, traditional electrical temperature measurement devices represented by thermistors cannot fully meet the requirements of integrated optoelectronic chips for temperature measurement and control. First, optoelectronic chips have high requirements for temperature accuracy, which need to reach 1 μK or even lower, while the temperature measurement accuracy of current commercial devices based on thermistors is 100 μK. Second, the materials and preparation processes of thermistors are not compatible with integrated optical devices, resulting in that the temperature measurement devices and integrated optical devices cannot be fabricated on the same wafer, increasing the processing and packaging difficulties. Third, the physical gap between the integrated optical device and the temperature measurement device brought by the packaging process causes the temperature sensed by the thermistor not to be the temperature on the surface or inside of the integrated optical device, which reduces the accuracy of temperature measurement.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present invention is to provide an integrated optical temperature sensing chip, an optical temperature sensing device, and a temperature measurement method, aiming to solve the problem that existing resistance sensors cannot accurately measure the temperature change of integrated optical devices.

[0006] The technical solution of the present invention is as follows:

[0007] An integrated optical temperature sensing chip, which includes a wafer substrate, and an integrated optical circuit disposed on the wafer substrate. The integrated optical circuit includes a closed-loop integrated optical resonator and an open-loop bus optical waveguide, and a coupling region is formed between the bus optical waveguide and the integrated optical resonator.

[0008] The integrated optical temperature sensing chip described above, wherein two orthogonally polarized modes are provided in the integrated optical resonator, and the difference in the resonance frequencies of the two orthogonally polarized modes changes with the change in the temperature of the integrated optical resonator.

[0009] The integrated optical temperature sensing chip described above, wherein the two orthogonally polarized modes are used to excite the laser into a transverse electric field wave and a transverse magnetic field wave respectively.

[0010] The integrated optical temperature sensing chip described above, wherein one end of the bus optical waveguide is an optical incident port, and the other end of the bus optical waveguide is an optical output port.

[0011] An optical temperature sensing device, which includes the integrated optical temperature sensing chip of the present invention.

[0012] The optical temperature sensing device described above, which includes a signal generator, a laser controller, a laser, a first optical polarization controller, an electro-optic phase modulator, a second optical polarization controller, an integrated optical temperature sensing chip, a third optical polarization controller, and a polarization beam splitter connected in sequence; one end of the polarization beam splitter is connected in sequence with a first photodetector, a first mixer, a low-pass filter, and a first proportional integral differential circuit, and the other end of the polarization beam splitter is connected in sequence with a second photodetector, a second mixer, a band-pass filter, a second proportional integral differential circuit, and a voltage controlled oscillator; the first proportional integral differential circuit is connected to the laser controller; both the first mixer and the second mixer are connected to the signal generator; the voltage controlled oscillator is connected to the electro-optic phase modulator.

[0013] The optical temperature sensing device described above, wherein the laser, the first optical polarization controller, the electro-optic phase modulator, the second optical polarization controller, the integrated optical temperature sensing chip, the third optical polarization controller, and the polarization beam splitter are connected by an optical path; the polarization beam splitter is connected to the first photodetector and the second photodetector respectively by an optical path; the signal generator is connected to the laser controller by an optical path; the first photodetector, the first mixer, the low-pass filter, the first proportional integral differential circuit, the laser controller, and the laser are connected in sequence by a circuit; the second photodetector, the second mixer, the band-pass filter, the second proportional integral differential circuit, the voltage controlled oscillator, and the electro-optic phase modulator are connected in sequence by a circuit.

[0014] A temperature measurement method based on the optical temperature sensing device of the present invention, which includes the steps:

[0015] The first proportional integral differential circuit applies a periodic triangular wave signal to the laser controller, causing the laser frequency f0 of the laser to linearly vary periodically; meanwhile, the signal generator generates a periodic sine modulation frequency Ω1 to drive the laser controller to modulate the laser; the modulated laser is coupled into the integrated optical temperature sensing chip after passing through the first optical polarization controller, the electro-optic phase modulator, and the second optical polarization controller in sequence;

[0016] The light coupled out from the integrated optical temperature sensing chip passes through the third optical polarization controller and the polarization beam splitter and is divided into two paths of light containing only one polarization mode. Among them, the light containing only one polarization mode P1 passes through the first photodetector and is converted into an electrical signal. The electrical signal and the modulation signal Ω1 generated by the signal generator generate a frequency discrimination signal E1 in the first mixer. The frequency discrimination signal E1 is converted into a control signal through the low-pass filter and the first proportional integral differential circuit and fed back to the laser controller; the other path of light containing only another polarization mode P2 passes through the second photodetector and is converted into an electrical signal. The electrical signal and the modulation signal Ω1 generated by the signal generator generate a frequency discrimination signal E2 in the second mixer. The frequency discrimination signal E2 is converted into a control signal through the band-pass filter and the second proportional integral differential circuit and fed back to the voltage-controlled oscillator;

[0017] The voltage-controlled oscillator applies a periodic sine signal Ω2 to the electro-optic phase modulator, causing the laser passing through the electro-optic phase modulator to generate sideband frequencies f0±Ω2 near the carrier frequency f0; by adjusting the DC input voltage of the voltage-controlled oscillator to change the modulation frequency Ω2, the sideband resonance peak of one polarization mode and the carrier resonance peak of the other polarization mode are made to coincide. At this time, the voltage-controlled oscillator frequency Ω2 is equal to the difference |f1 - f2| between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip;

[0018] The periodic triangular wave signal is turned off, and the laser frequency f0 is locked to the resonance frequency of one polarization mode of the integrated optical temperature sensing chip through the PDH frequency stabilization technology, and the voltage-controlled oscillator frequency Ω2 is locked to the difference |f1 - f2| between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip;

[0019] The frequency of the voltage-controlled oscillator in the locked state reflects the change information of the difference between the resonance frequencies of the two orthogonal polarization modes, that is, the change information of the temperature of the integrated optical temperature sensing chip; dividing the change amount Δ|f1 - f2| of the resonance frequency difference by the thermal sensitivity of the resonance frequency difference, Δ|f1 - f2| / dT, the temperature change ΔT sensed by the integrated optical temperature sensing chip can be obtained.

[0020] Beneficial effects: The present invention provides an integrated optical temperature sensing chip, an optical temperature sensing device, and a temperature measurement method. Based on the principle that the difference in the resonance frequencies of two orthogonal polarization modes changes with the change in the cavity temperature, through the PDH frequency locking technology, the frequency of the tunable laser is locked on one of the polarization resonance frequencies of the integrated optical resonator, and the sideband modulation frequency is locked on the difference between the resonance frequencies of the two orthogonal polarization modes, realizing the real-time tracking of the sideband modulation frequency with respect to the difference between the resonance frequencies of the two orthogonal polarization modes; by monitoring the change in the sideband modulation frequency, the accurate measurement of the temperature change of the integrated optical resonator is achieved. The advantages of the present invention are that the temperature of the sensor is measured by an optical method, the measurement accuracy is higher than that of a thermistor, and it does not interfere with the operation of photonic devices; the integrated optical temperature sensing chip is fabricated by semiconductor processes and can be integrated with other optoelectronic devices, reducing the manufacturing cost. Description of the Drawings

[0021] Figure 1 FIG. is a schematic structural diagram of a first perspective of an integrated optical temperature sensing chip of the present invention.

[0022] Figure 2 FIG. is a schematic structural diagram of a second perspective of an integrated optical temperature sensing chip of the present invention.

[0023] Figure 3 FIG. is a schematic diagram showing the change in the difference in frequencies of two orthogonal polarization modes of the present invention with the change in cavity temperature.

[0024] Figure 4 FIG. is a schematic structural diagram of an optical temperature sensing device of the present invention.

[0025] Figure 5 FIG. is a schematic diagram of the locked frequencies of the integrated optical temperature sensing chip. Detailed Embodiments

[0026] When measuring temperature by an optical method, no additional electronic devices need to be introduced, which will not affect the optical path transmission, and its measurement accuracy is also higher than that of thermistor devices. Based on the optical temperature measurement method of two orthogonal polarization modes, by utilizing the difference in the thermo-optic coefficients of the optical mode fields in two orthogonal polarization directions in an optical device, and by reading the change in the transmission properties of the optical mode fields in two orthogonal polarization directions in the optical device, the change in temperature in the device is deduced inversely, thereby realizing the accurate measurement of temperature changes. This method has been applied in a tabletop Fabry-Perot resonator and a whispering gallery resonator. However, these optical resonators have a relatively large cavity volume, and their fabrication processes are not compatible with semiconductor processes and cannot be integrated with other planar optical devices on the same wafer, thus limiting their application in temperature measurement of integrated optical chips.

[0027] Based on this, the present invention provides an integrated optical temperature sensing chip, as shown in Figure 1 and Figure 2As shown, it includes a wafer substrate 100, an integrated optical circuit disposed on the wafer substrate 100. The integrated optical circuit includes a closed-loop integrated optical resonator 200 and an open-loop bus optical waveguide 300. A coupling region 400 is formed between the bus optical waveguide 300 and the integrated optical resonator 200.

[0028] In this embodiment, the integrated optical temperature sensing chip is fabricated on the wafer substrate 100 in the form of an integrated planar optical circuit through semiconductor manufacturing technology. Two orthogonal polarization modes are provided in the integrated optical resonator 200. The difference between the resonance frequencies of the two orthogonal polarization modes changes with the change of the temperature of the integrated optical resonator. The optical waves of the two orthogonal polarization modes supported by the integrated optical temperature sensing chip are respectively transverse electric field waves and transverse magnetic field waves. The difference between the resonance frequencies of the transverse electric field waves and the transverse magnetic field waves changes with the change of the cavity temperature. As Figure 3 shown, if the resonance frequency position of one polarization mode is used as a reference point, the resonance frequency of the other polarization mode moves with the change of temperature; the polarization modes of the integrated optical resonator can be characterized by parameters such as resonance frequency, loaded quality factor, full width at half maximum, and extinction ratio within a certain laser frequency range. In this embodiment, one end of the bus optical waveguide is an optical input port, and the other end is an optical output port.

[0029] In this embodiment, an integrated optical resonator supporting two orthogonal polarization modes is fabricated on the wafer substrate by using semiconductor processing technology. By monitoring the relative change of the resonance frequencies of the two orthogonal polarization modes, the change of the temperature of the optical sensing chip is deduced inversely.

[0030] In some embodiments, the integrated optical temperature sensing chip can be individually packaged into an independent device, or integrated with other integrated optical circuits or integrated circuit devices on a wafer.

[0031] In some embodiments, an optical temperature sensing device is further provided, which includes the integrated optical temperature sensing chip of the present invention.

[0032] Specifically, as Figure 4As shown in the figure, the optical temperature measurement sensing device includes a signal generator 1, a laser controller 2, a laser 3, a first optical polarization controller 4, an electro-optic phase modulator 5, a second optical polarization controller 6, an integrated optical temperature measurement sensing chip 7, a third optical polarization controller 8, and a polarization beam splitter 9, which are connected in sequence; one end of the polarization beam splitter 9 is connected in sequence with a first photodetector 10, a first mixer 12, a low-pass filter 14, and a first proportional integral differential circuit 16, and the other end of the polarization beam splitter 9 is connected in sequence with a second photodetector 11, a second mixer 13, a band-pass filter 15, a second proportional integral differential circuit 17, and a voltage controlled oscillator 18; the first proportional integral differential circuit 16 is connected to the laser controller 2; both the first mixer 12 and the second mixer 13 are connected to the signal generator 1; the voltage controlled oscillator 18 is connected to the electro-optic phase modulator 5.

[0033] In this embodiment, the laser 3, the first optical polarization controller 4, the electro-optic phase modulator 5, the second optical polarization controller 6, the integrated optical temperature measurement sensing chip 7, the third optical polarization controller 8, and the polarization beam splitter 9 are connected by an optical path; the polarization beam splitter 9 is connected to the first photodetector 10 and the second photodetector 11 respectively by an optical path; the signal generator 1 is connected to the laser controller 2 by an optical path. The first photodetector 10, the first mixer 12, the low-pass filter 14, the first proportional integral differential circuit 16, the laser controller 2, and the laser 3 are connected in sequence by a circuit. The second photodetector 11, the second mixer 13, the band-pass filter 15, the second proportional integral differential circuit 17, the voltage controlled oscillator 18, and the electro-optic phase modulator 5 are connected in sequence by a circuit.

[0034] In this embodiment, the emitted laser of the laser is coupled into the integrated optical temperature measurement sensing chip, and the light exciting the transverse electric field wave and transverse magnetic field wave modes propagates in the optical waveguide; the frequency of the laser is locked at the resonance frequency of a polarization mode of the integrated optical resonator through the PDH frequency stabilization technology; the laser generates sidebands near the carrier through phase modulation; the frequency of the phase modulation is exactly the difference between the resonance frequencies of two orthogonal polarization modes in the integrated optical resonator; after phase modulation, the sideband frequency of the laser coincides with the resonance frequency of the other polarization mode of the integrated optical resonator; through the PDH frequency stabilization technology, the frequency of the phase modulation is locked as the difference between the resonance frequencies of two orthogonal polarization modes; the change in the temperature of the integrated optical resonator is obtained by monitoring the phase modulation frequency.

[0035] In some embodiments, a temperature measurement method based on the optical temperature measurement sensing device of the present invention is further provided, which includes the steps:

[0036] S10. The first proportional integral differential circuit 16 applies a periodic triangular wave signal to the laser controller 2, causing the laser frequency f0 of the laser 3 to linearly vary periodically. At the same time, the signal generator 1 generates a periodic sine modulation frequency Ω1 to drive the laser controller 2 to modulate the frequency f0 of the laser 3. The signal generator 1 is used to provide the required modulation and demodulation signals for the PDH frequency stabilization technology. The modulated laser passes through the first optical polarization controller 4, the electro-optic phase modulator 5, and the second optical polarization controller 6 in sequence and is then coupled into the integrated optical temperature sensing chip 7. Specifically, by adjusting the state of the second optical polarization controller 6, light waves of two orthogonal polarization modes can be excited in the bus optical waveguide and coupled into the integrated optical resonator.

[0037] S20. The light coupled out from the integrated optical temperature sensing chip 7 passes through the third optical polarization controller 8 and the polarization beam splitter 9 and is divided into two paths of light each containing only one polarization mode. Among them, the light of one path containing only one polarization mode P1 is converted into an electrical signal by the first photodetector 10. The electrical signal and the modulation signal Ω1 generated by the signal generator 1 generate a frequency discrimination signal E1 in the first mixer 12. The frequency discrimination signal E1 is converted into a control signal through the low-pass filter 14 and the first proportional integral differential circuit 16 and fed back to the laser controller 2. The light of the other path containing only the other polarization mode P2 is converted into an electrical signal by the second photodetector 11. The electrical signal and the modulation signal Ω1 generated by the signal generator 1 generate a frequency discrimination signal E2 in the second mixer 13. The frequency discrimination signal E2 is converted into a control signal through the band-pass filter 15 and the second proportional integral differential circuit 17 and fed back to the voltage-controlled oscillator 18.

[0038] S30. The voltage-controlled oscillator 18 applies a periodic sine signal Ω2 to the electro-optic phase modulator 5, causing the laser passing through the electro-optic phase modulator 5 to generate sideband frequencies f0±Ω2 near the carrier frequency f0. As Figure 5 shown, by adjusting the DC input voltage of the voltage-controlled oscillator 18 to change the modulation frequency Ω2, the sideband resonance peak of one polarization mode and the carrier resonance peak of the other polarization mode are made to coincide. At this time, the frequency Ω2 of the voltage-controlled oscillator is equal to the difference |f1 - f2| between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip.

[0039] S40. Turn off the periodic triangular wave signal, enable the servo modes of the first proportional integral differential circuit 16 and the second proportional integral differential circuit 17, and lock the laser frequency f0 at the resonance frequency of one polarization mode of the integrated optical temperature sensing chip through the PDH frequency stabilization technology, as Figure 5 at the solid line position shown; lock the frequency Ω2 of the voltage-controlled oscillator to the difference |f1 - f2| between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip, asFigure 5 as shown by the arrow

[0040] S50. The frequency of the voltage-controlled oscillator in the locked state reflects the change information of the difference between the resonant frequencies of two orthogonal polarization modes, that is, the change information of the temperature of the integrated optical temperature-sensing chip; dividing the change amount Δ|f1 - f2| of the difference between the resonant frequencies by the thermal sensitivity of the difference between the resonant frequencies, Δ|f1 - f2| / dT, the temperature change ΔT sensed by the integrated optical temperature-sensing chip can be obtained. Specifically, when the frequencies of both the laser 1 and the voltage-controlled oscillator 18 are locked by PDH frequency stabilization, by monitoring the change in the frequency Ω2 of the voltage-controlled oscillator 18, the change in the difference between the resonant frequencies of two orthogonal polarization modes in the integrated optical resonator 7 can be obtained, thereby knowing the change in the temperature of the integrated optical resonator 7 cavity; in addition, since the frequency of the voltage-controlled oscillator 18 is determined by its input signal, monitoring the frequency of the voltage-controlled oscillator 18 can also be achieved by monitoring its input control signal.

[0041] A temperature measurement method based on the optical temperature-sensing device of the present invention uses supporting optical and electrical devices to lock the laser frequency on the resonant frequency of one polarization mode and lock the voltage-controlled oscillator frequency on the difference between the resonant frequencies of two orthogonal polarization modes. By monitoring the change in the voltage-controlled oscillator frequency, the change in the temperature of the optical resonator cavity is obtained; this method measures the chip temperature using an optical signal, without introducing an additional thermistor device near the integrated photonic device, avoiding interference with the performance of the integrated photonic device; the optical and electrical devices used in this method have the potential for further on-chip integration, laying a foundation for the integration, miniaturization, and commercialization of high-temperature-stability integrated optoelectronic chips.

[0042] In summary, the present invention provides an integrated optical temperature-sensing chip, an optical temperature-sensing device, and a temperature measurement method. Based on the principle that the difference between the resonant frequencies of two orthogonal polarization modes changes with the change in the cavity temperature, through the PDH frequency-locking technology, the frequency of the tunable laser is locked on one polarization resonant frequency of the integrated optical resonator, and the sideband modulation frequency is locked on the difference between the resonant frequencies of two orthogonal polarization modes, realizing the real-time tracking of the sideband modulation frequency to the difference between the resonant frequencies of two orthogonal polarization modes; by monitoring the change in the sideband modulation frequency, the accurate measurement of the change in the temperature of the integrated optical resonator is achieved.

[0043] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. An integrated optical temperature sensing chip, characterized in that, It includes a wafer substrate, an integrated optical circuit disposed on the wafer substrate. The integrated optical circuit includes a closed-loop integrated optical resonator and an open-loop bus optical waveguide, and a coupling region is formed between the bus optical waveguide and the integrated optical resonator; Two orthogonally polarized modes are disposed in the integrated optical resonator, and the difference between the resonance frequencies of the two orthogonally polarized modes changes with the change of the temperature of the integrated optical resonator; The two orthogonally polarized modes are used to excite the laser into a transverse electric field wave and a transverse magnetic field wave respectively.

2. The integrated optical temperature sensing chip according to claim 1, wherein One end of the bus optical waveguide is a light incident port, and the other end of the bus optical waveguide is a light output port.

3. An optical temperature measurement sensing device, characterized in that, It includes the integrated optical temperature measurement and sensing chip according to any one of claims 1-2.

4. The optical temperature sensing device according to claim 3, wherein It includes a signal generator, a laser controller, a laser, a first optical polarization controller, an electro-optic phase modulator, a second optical polarization controller, an integrated optical temperature measurement and sensing chip, a third optical polarization controller, and a polarization beam splitter connected in sequence; one end of the polarization beam splitter is connected in sequence with a first photodetector, a first mixer, a low-pass filter, and a first proportional integral differential circuit, and the other end of the polarization beam splitter is connected in sequence with a second photodetector, a second mixer, a band-pass filter, a second proportional integral differential circuit, and a voltage controlled oscillator; The first proportional integral differential circuit is connected to the laser controller; both the first mixer and the second mixer are connected to the signal generator; the voltage controlled oscillator is connected to the electro-optic phase modulator.

5. The optical temperature measurement sensing device according to claim 4, characterized in that, The laser, the first optical polarization controller, the electro-optic phase modulator, the second optical polarization controller, the integrated optical temperature measurement and sensing chip, the third optical polarization controller, and the polarization beam splitter are connected by an optical path; the polarization beam splitter is connected to the first photodetector and the second photodetector respectively by an optical path; the signal generator is connected to the laser controller by an optical path; the first photodetector, the first mixer, the low-pass filter, the first proportional integral differential circuit, the laser controller, and the laser are connected in sequence by a circuit; the second photodetector, the second mixer, the band-pass filter, the second proportional integral differential circuit, the voltage controlled oscillator, and the electro-optic phase modulator are connected in sequence by a circuit.

6. A temperature measurement method for the optical temperature measurement sensing device according to any one of claims 4-5, characterized in that It includes steps: The first proportional integral differential circuit applies a periodic triangular wave signal to the laser controller, so that the laser frequency f0 of the laser changes linearly periodically; at the same time, the signal generator generates a periodic sine modulation frequency Ω1 to drive the laser controller to modulate the laser; The modulated laser is coupled into the integrated optical temperature measurement and sensing chip after passing through the first optical polarization controller, the electro-optic phase modulator, and the second optical polarization controller in sequence; The light coupled out from the integrated optical temperature sensing chip is divided into two paths of light containing only one polarization mode after passing through the third optical polarization controller and the polarization beam splitter. Among them, the light containing only one polarization mode P1 is converted into an electrical signal by the first photodetector. The electrical signal and the modulation signal Ω1 generated by the signal generator generate a frequency discrimination signal E1 in the first mixer. The frequency discrimination signal E1 is converted into a control signal through a low-pass filter and a first proportional integral differential circuit and fed back to the laser controller; the other path of light containing only another polarization mode P2 is converted into an electrical signal by the second photodetector. The electrical signal and the modulation signal Ω1 generated by the signal generator generate a frequency discrimination signal E2 in the second mixer. The frequency discrimination signal E2 is converted into a control signal through a band-pass filter and a second proportional integral differential circuit and fed back to the voltage controlled oscillator; The voltage controlled oscillator applies a periodic sine signal Ω2 to the electro-optic phase modulator, so that the laser passing through the electro-optic phase modulator generates sideband frequencies f0±Ω2 near the carrier frequency f0; by adjusting the DC input voltage of the voltage controlled oscillator to change the modulation frequency Ω2, so that the sideband resonance peak of one polarization mode coincides with the carrier resonance peak of the other polarization mode. At this time, the voltage controlled oscillator frequency Ω2 is equal to the difference between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip |f1 - f2|; Turn off the periodic triangular wave signal, and lock the laser frequency f0 on the resonance frequency of one polarization mode of the integrated optical temperature sensing chip through the PDH frequency stabilization technology, and lock the voltage controlled oscillator frequency Ω2 as the difference between the resonance frequencies of the two orthogonal polarization modes in the integrated optical temperature sensing chip |f1 - f2|; The frequency of the voltage controlled oscillator in the locked state reflects the change information of the difference between the resonance frequencies of the two orthogonal polarization modes, that is, the change information of the temperature of the integrated optical temperature sensing chip; divide the change amount Δ|f1 - f2| of the resonance frequency difference by the thermal sensitivity of the resonance frequency difference, Δ|f1 - f2| / dT, to obtain the temperature change ΔT sensed by the integrated optical temperature sensing chip.

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